Brine Feed System

ABSTRACT

The present invention relates to an electrolytic cell producing oxidants that utilizes a vacuum venturi system to meter saturated brine to the water stream to produce the correct conductivity electrolyte for operation of the electrolytic cell. The present invention comprises a venture eductor configured to accept brine from a brine source and to communicate brine to the chlorine generation system, a first control device to discourage communication of brine from the venture eductor to the brine source, and a second control device to control the rate of flow of brine from the brine source to the venture eductor.

FIELD OF THE INVENTION

The present invention relates to an electrolytic cell producing oxidantsthat utilizes a vacuum venturi system to meter saturated brine to thewater stream to produce the correct conductivity electrolyte foroperation of the electrolytic cell.

BACKGROUND

Electrolytic technology utilizing dimensionally stable anodes (DSA) hasbeen used for years for the production of chlorine and othermixed-oxidant solutions. Dimensionally stable anodes are described inU.S. Pat. No. 3,234,110 to Beer, entitled “Electrode and Method ofMaking Same,” whereby a noble metal coating is applied over a titaniumsubstrate.

An example of an electrolytic cell with membranes is described in U.S.Pat. RE 32,077 to deNora, et al., entitled “Electrode Cell with Membraneand Method for Making Same,” whereby a circular dimensionally stableanode is utilized with a membrane wrapped around the anode, and acathode concentrically located around the anode/membrane assembly.

An electrolytic cell with dimensionally stable anodes without membranesis described in U.S. Pat. No. 4,761,208 to Gram, et al., entitled“Electrolytic Method and Cell for Sterilizing Water.”

Commercial electrolytic cells have been used routinely for oxidantproduction that utilize a flow-through configuration that may or may notbe under pressure that is adequate to create flow through theelectrolytic device. Examples of cells of this configuration aredescribed in U.S. Pat. No. 6,309,523 to Prasnikar, et al., entitled“Electrode and Electrolytic Cell Containing Same,” and U.S. Pat. No.5,385,711 to Baker, et al., entitled “Electrolytic Cell for GeneratingSterilization Solutions Having Increased Ozone Content,” and many othermembrane-type cells.

In other configurations, the oxidant is produced in an open-type cell ordrawn into the cell with a syringe or pump-type device, such asdescribed in U.S. Pat. No. 6,524,475 to Herrington, et al., entitled“Portable Water Disinfection System.”

U.S. Pat. No. 7,005,075 to Herrington, et al., entitled “Gas DriveElectrolytic Cell,” teaches a disinfection device that incorporates anelectrolyte solution and a gas head space within a closed electrolyticcell chamber. During electrolysis of electrolyte to a disinfectantsolution, hydrogen gas is generated within the closed electrolytic cellthereby generating pressure within the closed cell. Upon completion ofelectrolysis of the electrolyte solution to produce the disinfectantsolution, a discharge port on the electrolytic cell housing is opened.Gas pressure within the cell housing provides the motive force to expelall or most of the disinfectant out of the cell housing to such a pointwhere the disinfectant solution is utilized. By definition, this deviceoperates in batch mode.

U.S. Pat. No. 7,922,890 to Sanchez, et al, entitled “Low MaintenanceOn-Site Generator” describes methods for precisely controlling waterflow to an electrolytic cell system in order to maintain stable waterflow conditions to the cell. This patent teaches a fully saturated brinemetering system utilizing a variable speed brine pump.

DESCRIPTION OF INVENTION, MODES FOR CARRYING OUT THE INVENTION ANDINDUSTRIAL APPLICABILITY

The present invention relates to an electrolytic cell producing oxidantsthat utilizes a vacuum venturi system to meter saturated brine to thewater stream to produce the correct conductivity electrolyte foroperation of the electrolytic cell. The present invention comprises aventure eductor configured to accept brine from a brine source and tocommunicate brine to the chlorine generation system, a first controldevice to discourage communication of brine from the venture eductor tothe brine source, and a second control device to control the rate offlow of brine from the brine source to the venture eductor. The firstflow device can comprise, as an example, a check valve. The secondcontrol device can comprise, as examples, one or more of a manual valve,a solenoid controlled valve, an air controlled valve, and a motorcontrolled valve.

FIG. 1 represents a commercial system of the present art 60 that uses avariable speed gear type brine metering pump 68 or a bellows type pumpto meter brine into main water stream 62 entering electrolytic cell 70where brine is converted to halogen oxidants that are transferred tooxidant tank 72. Brine generation is produced in brine generator 64,passes through brine filter 66 and is metered by brine pump 68 toachieve the appropriate concentration for electrolysis in cell 70. Alloperations are controlled automatically by power supply/controllersystem 74.

In an example embodiment of the present invention shown in system 20 inFIG. 2, brine from brine generator 32 is metered in to water supply 28via venturi 22 that creates a vacuum on the brine source in brinegenerator 36 and said brine is filtered by filter 38 which is then drawnby vacuum through variable control valve 24 into venturi 22. Feed wateris cleaned by water filter 30 and calcium is removed from the water viawater softener 32 to eliminate scale buildup in cell 34. To control backflow of water to brine generator 36 under certain operating or standbyconditions, check valve 26 precludes back flow of water to brinegenerator 36. Power supply/controller 42 precisely controls the flow offully saturated brine to the water fluid stream entering electrolyticcell 34 via an analog control scheme that precisely opens and controlsvariable control valve 24 to maintain the correct electricalconductivity in cell 34 for electrolysis. Current methods of brine fluidcontrol in the industry use expensive pumps to precisely meter the brineto the main water stream. The present invention is a much simpler andlower cost method and has no pump components to wear out, thereby makingthe brine metering process simpler, lower cost, and much more reliable.The system can be manually controlled or can be automated and simplifiedfor the operator. The control scheme for electrolytic systems todayutilize amperage or voltage monitoring systems at the electrolytic cellwhich are controlled by a power supply/controller 74 like that shown inFIG. 1. For voltage controlled systems, brine metering pump 68 can be,for example, a bellows type pump that is set to operate at a fixed flowrate. To control consistent concentration of oxidant from theelectrolytic cell, in some cases sodium hypochlorite, the voltageapplied to the cell is adjusted to maintain the correct amperage valuein the electrolytic cell. In this manner, as the cell loses efficiency,for example due to carbonate scale buildup on the cathode electrode incell 70, energy efficiency is lost due to the application of more powerto the cell. However, brine conversion efficiency is maintained. In analternate example control scheme, voltage is maintained constant and theconductivity of the electrolyte in the cell is adjusted to maintain thecorrect amperage on the cell. Conductivity is adjusted by varying therate of concentrated brine flow to the water stream entering cell 70 toincrease conductivity as cell 70 loses efficiency. In the present art,the concentrated brine flow is adjusted, or varied, by utilizing a geartype brine pump that is driven by a variable speed motor. The controlscheme monitors the cell amperage. If the amperage drops below a definedvalue, the control system sends a signal to brine pump motor 68 toincrease speed. In this manner more fully saturated brine is metered tothe water stream entering cell 70, the conductivity of the electrolyte(water and brine) entering cell 70 will allow more amperage to flow fromthe anode to the cathode electrodes in cell 70, thereby increasing thepower drawn from power supply/controller 74. In this manner, theconcentration of the oxidant produced in cell 70 will be maintained.This allows a consistent concentration of oxidant delivered to oxidantstorage tank 72. Consistent concentration of oxidant in oxidant storagetank 72 allows consistent metering of oxidant to the water source beingdisinfected so that the dose of oxidant to the main water source isconsistent.

In the example embodiment of the present invention shown in FIG. 2, aventuri injector 22 such as those manufactured by Mazzei Corporation, ismounted in water line 28 feeding water to electrolytic cell 34. A vacuumis created in the throat of venturi injector 22. The vacuum port onventuri injector 22 is connected to saturated brine feed tank 36. Checkvalve 26 can be incorporated in venturi injector 22 vacuum port so thatwater flowing in venturi injector 22 cannot flow out the vacuum portwhen the flow of water in venturi injector 22 is static. The vacuum porton venturi injector 22 is also connected to variable control valve 24which is then routed to brine generator 36 that converts dry halide salt(typically sodium chloride) to fully saturated brine. Electrolytic cell34 in this scheme has a fixed voltage applied. Power supply/controller42 monitors amperage applied to cell 34. If the amperage is below apredefined value, then the control scheme opens variable control valve24 slightly to increase the flow of brine through variable control valve24. In this way the brine concentration of the fluid entering cell 34 isincreased thereby increasing the conductivity of the solution(electrolyte) entering cell 34 which thereby increases the amperage drawon cell 34. In this manner, the concentration of the halide oxidantproduced in cell 34, typically sodium hypochlorite or mixed oxidants, isincreased. Conversely, if the amperage in cell 34 is too high, powersupply/controller 42 reduces the flow of brine through variable controlvalve 24 thereby decreasing the conductivity of the electrolyte. Withthis scheme, the concentration of the oxidant produced in electrolyticcell 34 can be maintained within a few small percentage points of thedesired concentration set point for the oxidant in oxidant storage tank40.

Other objects, advantages and novel features, and further scope ofapplicability of the present invention will become apparent to thoseskilled in the art upon examination of the present specification,claims, and figures, or can be learned by practice of the invention. Theobjects and advantages of the invention can be realized and attained bymeans of the instrumentalities and combinations particularly pointed outin the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a control scheme for an electrolytic on-site generation systemutilizing a variable control brine feed pump to meter brine to anelectrolytic cell.

FIG. 2 is a control scheme for an electrolytic on-site generation systemutilizing a venturi injector and variable control solenoid valve tometer brine to an electrolytic cell.

1. A brine metering system for supplying brine to a chlorine generationsystem, comprising a venture eductor configured to accept brine from abrine source and to communicate brine to the chlorine generation system,a first control device to discourage communication of brine from theventure eductor to the brine source, and a second control device tocontrol the rate of flow of brine from the brine source to the ventureeductor.
 2. A brine metering system as in claim 1, wherein the firstcontrol device comprises a check valve.
 3. A brine metering system as inclaim 1, wherein the second control device comprises a manual valve. 4.A brine metering system as in claim 1, wherein the second control devicecomprises a variable control solenoid valve.
 5. A brine metering systemas in claim 1, wherein the second control device comprises a motorcontrolled valve.
 6. A brine metering system as in claim 1, wherein thesecond control device comprises an air controlled valve.
 7. A brinemetering system as in claim 2, wherein the second control devicecomprises a manual valve.
 8. A brine metering system as in claim 2,wherein the second control device comprises a variable control solenoidvalve.
 9. A brine metering system as in claim 2, wherein the secondcontrol device comprises a motor controlled valve.
 10. A brine meteringsystem as in claim 2, wherein the second control device comprises an aircontrolled valve.